In summer, ceiling fans are very effective at lowering the apparent temperature by making use of evaporation. When you are hot, you perspire, perhaps only a small amount. This is the body's way of cooling off - Evaporation of the perspiration pulls heat away from your body. Circulation of the air rapidly increases evaporation. The more evaporation, the cooler the apparent temperature. This means the thermostat on the A/C can be set higher saving you money.In the Cold Season, with the reverse switch set for an upward airflow (clockwise), running your fan on low speed will force the heat accumulated at the ceiling down along the walls where it must rise again. This mild circulation of air provides a more evenly heated room, shortening the time it takes the heater to work. (Low speed is highly recommended to avoid drafts.)